PC

Temp

256 C

50 C

4096

§

·

u

q

q

¨

¸

©

¹

Power

Off

54ms

max

Pulse

Train

Start of next

conversion result data

50ms max

End of data

Power

Start of data

transmission

End of data

104ms max

50ms max

Power

ON

11

LMT01-SP

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SNIS205 – JANUARY 2019

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Copyright © 2019, Texas Instruments Incorporated

Feature Description (continued)

Figure 19. Temperature to Digital Pulse Train Timing Cycle

7.3.2 Output Transfer Function

The LMT01-SP outputs at minimum 1 pulse and a theoretical maximum 4095 pulses. Each pulse has a weight of

0.0625°C. One pulse corresponds to a temperature less than –50°C while a pulse count of 4096 corresponds to

a temperature greater than 200°C. Note that the LMT01-SP is only ensured to operate up to 125°C, but is

functional up to 150°C. Exceeding this temperature by more than 5°C may damage the device. The accuracy of

the device degrades as well when 125°C is exceeded.

Two different methods of converting the pulse count to a temperature value are discussed in this section. The

first method is the least accurate and uses a first order equation, and the second method is the most accurate

and uses linear interpolation of the values found in the look-up table (LUT) as described in Electrical

Characteristics - Pulse Count to Temperature LUT.

The output transfer function appears to be linear and can be approximated by Equation 1:

where

•

PC is the Pulse Count

•

Temp is the temperature reading

(1)

Table 1 shows some sample calculations using Equation 1.

Table 1. Sample Calculations Using Equation 1

TEMPERATURE (°C)

NUMBER OF PULSES

–49.9375

1

–49.875

2

–40

160

–20

480

0

800

30

1280

50

1600

100

2400

150

3200